Approvals in a SharePoint document library

A really important step to start with is to check the Microsoft 365 Audit log in the compliance portal. Search for activities like “FileModified” or “FileUpdated” right after you approve a file. That can show exactly what account or process is changing the item. If it’s a flow, you’ll often see the user or service account that owns the flow. Also check the run history of any Power Automate flows connected to the library to see if one triggered at that time.

Below are the possible reasons and fix:

• Automatic metadata updates from sensitivity/retention labels, compliance policies, or DLP rules
• Thumbnail/previews or search-indexing processes that rewrite file properties
• The OneDrive sync client re-uploading changes to the file
• Any Power Automate flow or script writing to the item, even to a “hidden” column

Because none of these bump the major version, you won’t see an entry in Version History but the approval request is cancelled all the same.

To fix:

• Review and scope your auto-labeling or retention policies so they don’t apply to this library (or turn them off temporarily).
• Disable OneDrive sync for that library (or exclude the folder).
• Audit any flows or event receivers that write metadata back to items.
•  If you need approval to survive metadata changes, replace the built-in approvals with a Power Automate approval flow those won’t reset on metadata edits.